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Article

The Design of Sulfated Ce/HZSM-5 for Catalytic Decomposition of CF4

by
Xie Zheng
1,2,
Shijie Chen
1,2,
Wanning Liu
1,2,
Kaisong Xiang
2,3,* and
Hui Liu
1,2
1
School of Metallurgy and Environment, Central South University, Changsha 410083, China
2
Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
3
School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
*
Author to whom correspondence should be addressed.
Polymers 2022, 14(13), 2717; https://doi.org/10.3390/polym14132717
Submission received: 7 June 2022 / Revised: 23 June 2022 / Accepted: 30 June 2022 / Published: 2 July 2022
(This article belongs to the Section Polymer Analysis and Characterization)
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Abstract

:
CF4 has a global warming potential of 6500 and possesses a lifetime of 50,000 years. In this study, we modified the HZSM-5 catalyst with Ce and sulfuric acid treatment. The S/Ce/HZSM-5 catalyst achieves 41% of CF4 conversion at 500 °C, which is four times higher than that over Ce/HZSM-5, while the HZSM-5 exhibits no catalytic activity. The effects of modification were studied by using NH3-TPD, FT-IR of pyridine adsorption, and XPS methods. The results indicated that the modification, especially the sulfuric acid treatment, strongly increased the Lewis acidic sites, strong acidic sites, and moderate acidic sites on catalysts, which are the main active centers for CF4 decomposition. The mechanism of acidic sites increases by modification and CF4 decomposition is clarified. The results of this work will help the development of more effective catalysts for CF4 decomposition.

1. Introduction

Perfluorocarbon (PFC) is a class of greenhouse-gas (GHG) in which all valences of carbon are satisfied with fluorine atoms [1,2]. CF4 is considered as the most abundant and harmful in PFCs, and it has a high global warming potential, which is about 6500 times higher than that of CO2 over a 100-year time scale [3]. Due to its symmetry and strong ionic character in the C–F covalent bond, which is the strongest bond (543 kJ mol−1) in organic chemistry, the CF4 molecule is extremely stable [4]. The aluminum production industry is considered as the main source of CF4 emission. When the anode effect occurs in the electrolytic cell, the flux Na3AlF6 will react with the C anode to form CF4 as in the equation below [5]. In 2018, the global CF4 emission from aluminum production is 4.408 Gg, accounting for approximately 4% of total GHG emission in CO2 equivalent [6]. However, the lifetime of CF4 in atmosphere is 50,000 years while that of CO2 is only 10–20 years. Therefore, it is necessary and important to remove CF4 presented in the exhaust flue gas from the aluminum production industry.
4Na3AlF6 + 3C → 4Al + 12NaF + 3CF4
To date, several methods have been developed for CF4 abatement, such as fueled combustion, plasma, and catalytic hydrolytic decomposition [7,8,9]. Among them, the catalytic hydrolytic decomposition is considered as the ideal method for its high efficiency and mild reaction temperature compared to others.
HZSM-5 is a molecular sieve catalyst with Si, Al, and O elements as the framework, it has displayed excellent performance in chlorofluorocarbon and hydrofluorocarbon decomposition [10,11,12,13]. The catalytic behavior is related to its high specific surface area, strong acidity, and three-dimensional channel system. However, the amount of strong acidic sites and Lewis acidic sites are insufficient for CF4 decomposition.
Cerium (Ce) is a good promoter for catalyst, due to its high oxygen-storage capacity, high oxygen-vacancy concentration, and the facile Ce4+/Ce3+ redox cycle, which enhances the electron transfer that generates more acidic sites [14,15]. For example, de Rivas et al. [12] studied the 1,2-dichloroethane decomposition over the Ce/HZSM-5 catalyst, and they achieved a 90% conversion that was attributed to the addition of Ce which increased the Lewis acidic sites. Chen et al. [16] synthesized a [Ce-(1,3,5-benzenetricarboxylic acid)(H2O)6] catalyst, and achieved a good activity for toluene oxidation with conversion of T90% at 223 °C, the authors concluded that the catalytic activity was due to the great amount of acidic sites on catalyst. Moreover, some research suggests that the sulfuric acid treatment is an excellent strategy to significantly increase the Lewis acidic sites on catalysts, as the sulfate ions act as Lewis acidic sites; meanwhile, they attracted electrons to create more new acidic sites [17,18]. Song et al. [19] modified the γ-Al2O3 with Ce and sulfuric acid treatment for CF4 catalytic decomposition, and found that the addition of Ce increased the acidic sites, the sulfuric acid treatment further enhanced the increasement, and the CF4 conversions were consistent with the amount of acidic sites. Although varied Lewis acid type catalysts can be applied in CF4 decomposition, a high temperature (over 700 °C) is required to decompose the CF4 molecule [20,21,22]. Therefore, we focused on developing a HZSM-5 based catalyst by modification with element Ce and sulfuric acid treatment for CF4 decomposition below 700 °C.
Given the above reasons, a series of modified HZSM-5 catalysts were developed to hydrolytic decompose CF4 at 500 °C. The aim of this work is to investigate the changes in the properties of the catalyst on the addition of Ce and acid treatment. The physicochemical properties of catalysts were characterized by different techniques. This study intended to elucidate the mechanisms of CF4 decomposition over HZSM-5 based catalysts.

2. Experimental Section

2.1. Catalyst Preparation

The Ce/HZSM-5 catalyst was prepared using the impregnation–calcination method from the commercial molecular sieve HZSM-5 (Si/Al = 18, mole ratio, Nankai Unv, Tianjin, China) calcined at 650 °C in N2 atmosphere for 5 h with an aqueous solution containing required amounts of cerium nitrate (Sinopharm Chemical Reagent Co., Ltd., Shanghai, China), followed by drying overnight at 80 °C. The Ce/HZSM-5 (10%Ce/HZSM-5) catalyst was crushed and sieved into 60–80 mesh. The Ce/HZSM-5 catalyst was impregnated with an aqueous solution containing H2SO4 (98%, Sinopharm Chemical Reagent Co., Ltd., Shanghai, China) under stirring for 24 h and dry for 12 h at 60 °C, the impregnating solution was adjusted to yield the same SO42− (12 wt%) as S/Ce/HZSM-5, finally, calcined at 650 °C for 5 h in N2 atmosphere. The S/Ce/HZSM-5 (12%S/10%Ce/HZSM-5) catalyst was crushed and sieved into 60–80 mesh.

2.2. Catalytic Activity Test

The hydrolytic decomposition of CF4 was carried out in a fixed-bed reactor. The temperature was maintained at 500 °C. In the aluminum production, the CF4 generated in electrolytic cell during the anode effect, the CF4 concentration in the flue gas is about 1%. Therefore, the gas flow consists of l% CF4, 35% H2O, and balanced by Ar. The water was pre-heated at 150 °C and then constantly introduced into the reaction system by using a syringe pump. The effluent gas was washed by aqueous potassium hydroxide to remove the produced HF, and then passed through a cold trap to remove water. Finally, the gas was analyzed by an online gas chromatography (GC-9790 II) equipped with a thermal conductivity detector (TCD).

2.3. Catalyst Characterization

The morphology of the samples was examined by scanning electron microscope (SEM, JSM-IT300LA, JEOL, Tokyo, Japan) with energy dispersive X-ray (EDX) analysis. The X-ray diffraction analysis was performed on a TTR III diffractometer (XRD, Rigaku, Tokyo, Japan). The chemical composition and state of the elements on catalyst surfaces were investigated by X-ray photoelectron spectroscopy (XPS, EscaLab 250Xi, Thermo Fisher, Waltham, MA, USA). The specific surface areas were measured with the N2 adsorption method on an ASAP analyzer (BET, ASAP2020, Micromeritics, Norcross, GA, USA). Ammonia temperature programmed desorption (NH3-TPD, AutoChem II 2920, Micromeritics, Norcross, GA, USA) analyses were performed using the following procedures. A 100 mg sample was pretreated at 550 °C, with helium flow of 30 mL/min for 1 h, and then cooled to 50 °C. Ammonia (10% NH3/He) was introduced to the catalyst for 1 h at 50 °C. After that, the sample was flushed with helium of 50 mL/min for 1 h to remove absorbed NH3, then the temperature was programmed to increase to 900 °C at a rate of 10 °C/min. The amount of ammonia desorbed from the catalyst was detected using TCD. Fourier transform infrared spectra (FT-IR, Nicolet iS50, Thermo Fisher, Waltham, MA, USA) of pyridine absorption were conducted using the following procedures. The sample was pressed and put into an IR cell, and then it was degassed at 400 °C under vacuum for 2 h to dehydrate. Next, the cell was cooled to room temperature, and the background signal was recorded. After that, pyridine vapor was introduced to the system until reaching adsorption equilibrium. The sample was evacuated out at 150 °C for 30 min followed by cooling down to 50 °C, and then spectral acquisition was performed.

3. Results and Discussion

3.1. Characterization of Catalysts

The morphology and elemental distribution of catalysts were monitored by SEM and EDS mapping, as shown in Figure 1. The microscopic images of HZSM-5 (Figure 1A) exhibit the nano-blocky particles with a smooth surface. The modified catalyst Ce/HZSM-5 (Figure 1B) and the S/Ce/HZSM-5 (Figure 1C,D) exhibit rough surface, the catalysts were covered by small solid granule. The EDS mapping for S/Ce/HZSM-5 (Figure 1E–I) exhibits the uniform distribution of O, Si, Al, S and Ce, respectively.
The X-ray diffraction (XRD) was performed to investigate the crystal structure of the catalysts as in Figure 2. All the samples contain the HZSM-5 [23], and the peak of CeO2 (JCPDS:34-0394) is observed in modified samples, indicating the formation of CeO2 [24]. It should be noted that the peak of Ce2(SO4)3 is not observed in the S/Ce/HZSM-5 catalyst, which indicated the absence of reaction between Ce and sulfuric acid during the catalyst preparation step. The specific surface area and pore diameter of catalysts were analyzed, as listed in Table 1. The surface area of catalysts decreased from 248 m2 g−1 to 148 m2 g−1, and the pore diameter decreased from 2.38 nm to 2.28 nm after modified by Ce, these changes are in agreement with previous research [19,25], which may account for the formation of CeO2 on the surface of catalysts, in addition to element Ce, some cation ions were replaced by Ce, the CeO2 would block the original pore, results in the surface area and pore diameter decreasing. The surface area and pore diameter increased to 278 m2 g−1 and 2.28 nm, respectively, after the sulfate acid treatment. This may be due to the fact that acid treatment increased the amount of amorphous silica [26].
The NH3-TPD experiments were conducted to analyze the different kinds of acidic sites in the catalysts. There are three kinds of acidic site according to the desorption temperature of NH3 on catalysts: weak acidic sites (T < 250 °C), moderate acidic sites (250 °C < T < 600 °C), and strong acidic sites (T > 600 °C) [27,28,29]. The TPD results are shown in Figure 3 and Table 2, the HZSM-5 catalyst exhibited the most weak acidic sites (663 µmol g−1) and the second highest amount of moderate acidic sites (267 µmol g−1), the strong acidic site was not observed. The addition of Ce decreased the amount of weak acidic sites to 290 µmol g−1 and increased the moderate acidic sites to 544 µmol g−1, but still, no strong acidic site was observed. After further acid treatment, the amount of weak acidic sites decreased to 273 µmol g−1 and the amount of moderate acidic sites increased to 855 µmol g−1, the amount of strong acidic sites dramatically increased to 1274 µmol g−1, which dominated over others. These findings strongly indicated that the impregnation with sulfate group influenced the acidic properties of catalysts, the amount of moderate and strong acidic sites significantly increased; moreover, the ratio of (strong + moderate)/weak was in the following order: S/Ce/HZSM-5(7.80) > Ce/HZSM-5(1.88) > HZSM-5(0.40).
In order to gain more information on acidic properties of catalysts, the FT-IR spectra of pyridine adsorption experiments are conducted as shown in Figure 4 and Table 3. The spectra are recorded over a frequency range from 1400 cm−1 to 1700 cm−1, where characteristic vibration modes of adsorbed pyridine will appear. According to the references [30,31], the characteristic wave number of 1455 cm−1, 1612 cm−1 could be assigned to the pyridine species coordinatively adsorbed on Lewis acid sites, while the wave number of 1545 cm−1, 1635 cm−1 assigned to pyridinium ion formed on Brønsted acid sites, the 1490 peak was attributable to the L+B acid sites. The amounts of L-acid site on HZSM-5, Ce/HZSM-5 and S/Ce/HZSM-5 were 120.57 µmol g−1, 138.26 µmol g−1 and 156.84 µmol g−1, respectively. The amount of Brønsted acid sites showed the reversed trend, they were 233.91 µmol g−1, 83.61 µmol g−1 and 69.97 µmol g−1, respectively. The ratio of Lewis/Brønsted was in the following order: S/Ce/HZSM-5(2.24) > Ce/HZSM-5(1.65) > HZSM-5(0.52). The results indicated that the addition of Ce increased the amount of Lewis acidic sites while decreasing the Brønsted acidic sites; furthermore, the acid treatment enhanced the influence.

3.2. Catalytic Performance of CF4 Decomposition

The conversion reactions of CF4 over catalysts were conducted at different temperature, as shown in Figure 5. The HZSM-5 exhibited no catalytic activity below 600 °C, and only 14% conversion of CF4 while the temperature increased up to 700 °C. The Ce/HZSM-5 exhibited a higher CF4 conversion compared to HZSM-5, the CF4 conversions at 500 °C, 550 °C, 600 °C, 650 °C and 700 °C were 10%, 41%, 52%, 60% and 63%, respectively. As for the S/Ce/HZSM-5 catalyst, the CF4 conversion was further enhanced, they were 41%, 50%, 63%, 66% and 67%, respectively. Moreover, at the temperature of 500 °C, the conversion of S/Ce/HZSM-5 was four times higher than that of Ce/HZSM-5. These results indicated that the acid treatment significantly increased the catalytic activity of Ce/HZSM-5, which showed a good agreement with the results of BET, NH3-TPD and FT-IR.
The stability of catalysts was tested for 60 h at 500 °C as shown in Figure 6. The CF4 conversion over S/Ce/HZSM-5 decreased from 41% to 34% (17% loss), while the conversion over Ce/HZSM-5 decreased from 11% to 7% (27% loss). The catalytic stability of S/Ce/HZSM-5 was much higher than that of Ce/HZSM-5. This may be due to the increment of acidic sites by acid treatment.

3.3. Mechanism Analysis of Hydrolytic Decomposition of CF4

In order to demonstrate the main factor that promoted the catalytic activity of catalysts, the close correlation between CF4 conversion and the ratio of (strong + moderate)/weak and Lewis/Brønsted were performed as shown in Figure 7. The correlation showed that the conversion is related to the ratio of (strong + moderate)/weak and the ratio of Lewis/Brønsted. Therefore, we concluded that the strong + moderate acidic sites and the Lewis acidic sites, are the main factor that promoted the activity of the catalysts. The HZSM-5 exhibited no catalytic activity due to its low ratio of (strong + moderate)/weak and Lewis/Brønsted. Similarly, it has been reported that the Lewis acid sites and strong + moderate acid sites played a promoting role in the decomposition of hydrofluorocarbons [32,33,34]. The results strongly suggest that the direct participation of the acid sites in CF4 decomposition is probably a step for subtracting fluorine atom from CF4 molecule by Lewis acid sites. The addition of element Ce and the acid treatment could significantly influence the acidic property, resulting in increasing the catalytic activity and stability of catalysts in CF4 decomposition.
In order to acquire insights into the surface chemical composition of catalysts, X-ray photoelectron spectroscopy (XPS) analysis of catalysts was carried out and shown in Figure 8 and Table 4. A curve-fitting for this analysis was carried out after Shirley-type background subtraction using a combination of Gaussian and Lorentzian functions. Figure 8A presented the S 2p core level spectra, the two major binding energy values were located at 168.90 eV and 170.10 eV, attributing to S 2p1/2 and S 2p2/3 respectively, which were ascribed to S6+ from SO42−. According to references [17,18,35], the S6+ from SO42− could significantly increase the amount of Lewis acidic sites, which showed a good agreement with the results of NH3-TPD and FT-IR. The O 1s core level spectra of catalysts were shown in Figure 8B, there are three major binding energy values located at range 528.9 to 529.5 eV, range 530.0 to 531.6 eV, and range 531.9 to 533.2 eV, attributing to Olat, Osur and Oads, respectively [36,37]. After the acid treatment, the peak of Olat disappeared, the intensity of peak for Oads increased, it could be concluded that the Olat were transformed to Oads, meanwhile, some of the Olat bonded with S6+ to form SO42−, then increased the amount of Lewis acidic sites. The Ce 3d core level spectra of catalysts are shown in Figure 8C, the peak v2 (885.9 eV–886.3 eV) and peak u2 (904.0 eV–904.5 eV) were ascribed to Ce3+, the peak v1 (883.0 eV), peak v3 (887.3 eV–889.1 eV), peak v4 (898.8 eV), peak u1 (901.5 eV), peak u3 (905.9 eV–907.7 eV) and peak u4 (917.3 eV) were ascribed to Ce4+ [38,39], after the sulfuric acid treatment, the peak u4 and peak v4 disappeared, the Ce3+/Ce increased from 25.9% to 31.0%, indicating that the sulfuric acid treatment reduced the Ce4+ to Ce3+ because they attracted electrons to create more Lewis acidic sites, which showed a good agreement with the CF4 conversion performance and the results of NH3-TPD and FT-IR.

4. Conclusions

We modified the commercial HZSM-5 with the addition of Ce(Ce/HZSM-5) and further sulfuric acid treatment (S/Ce/HZSM-5). The S/Ce/HZSM-5 catalyst achieved a 41% CF4 conversion at 500 °C which is four times higher than that over Ce/HZSM-5, while the HZSM-5 exhibited no catalytic activity. The close correlation between CF4 catalytic conversion and acidic property indicated that the Lewis acidic sites and moderate + strong acidic sites are the main factors that promoted the activity of the catalysts. The effects of modification were confirmed by using NH3-TPD, FT-IR of pyridine adsorption and XPS methods. These results indicate that the acidity properties of catalysts are strongly influenced by the addition of Ce and further sulfuric acid treatment, and then significantly improved the catalytic activity in the CF4 decomposition process, which is an acid-catalyzed reaction.

Author Contributions

All authors contributed to the study conception and design, X.Z., S.C. and W.L. developed and designed the methodology of this experiment. X.Z. prepared the original draft and K.X. revised the manuscript. H.L. supervised the project and had leadership responsibility for the research. All authors have read and agreed to the published version of the manuscript.

Funding

This work was financially supported by National Natural Science Foundation of China (51974378), Innovative Research Group Project of the National Natural Science Foundation of China (52121004) and Special Funding for Innovative Province Construction of Hunan (2019RS3006).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data supporting this study are available from the corresponding author upon reasonable request.

Conflicts of Interest

The authors declare no competing interest.

References

  1. O’Hagan, D. Understanding organofluorine chemistry. An introduction to the C–F bond. Chem. Soc. Rev. 2008, 37, 308–319. [Google Scholar] [CrossRef] [PubMed]
  2. Hannus, I. Adsorption and transformation of halogenated hydrocarbons over zeolites. Appl. Catal. A Gen. 1999, 189, 263–276. [Google Scholar] [CrossRef]
  3. Mühle, J.; Ganesan, A.L.; Miller, B.R.; Salameh, P.K.; Harth, C.M.; Greally, B.R.; Rigby, M.; Porter, L.W.; Steele, L.P.; Trudinger, C.M.; et al. Perfluorocarbons in the global atmosphere: Tetrafluoromethane, hexafluoroethane, and octafluoropropane. Atmos. Chem. Phys. 2010, 10, 5145–5164. [Google Scholar] [CrossRef] [Green Version]
  4. Tsai, W.T.; Chen, H.P.; Hsien, W.Y. A review of uses, environmental hazards and recovery/recycle technologies of perfluorocarbons (PFCs) emissions from the semiconductor manufacturing processes. J. Loss Prevent. Proc. Ind. 2002, 15, 65–75. [Google Scholar] [CrossRef]
  5. Tabereaux, A.T. Anode effects, PFCs, global warming, and the aluminum industry. J. Miner. Met. Mater. Soc. (TMS) 1994, 46, 30–34. [Google Scholar] [CrossRef]
  6. Perfluorocarbon (PFC) Emissions—International Aluminium Institute. Available online: https://international-aluminium.org/ (accessed on 5 June 2022).
  7. Zheng, X.; Zheng, X.; Xiang, K.; Shen, F.; Liu, H. The Zr Modified γ-Al2O3 Catalysts for Stable Hydrolytic Decomposition of CF4 at Low Temperature. Catalysts 2022, 12, 313. [Google Scholar] [CrossRef]
  8. Jia, L.; Ma, S. The Experimental Study on High Temperature Air Combustion and CF4 Decomposition. In Proceedings of the Heat Transfer Summer Conference, San Francisco, CA, USA, 17–22 July 2005; pp. 705–708. [Google Scholar]
  9. Efremov, A.; Lee, J.; Kim, J. On the Control of Plasma Parameters and Active Species Kinetics in CF4/O2/Ar Gas Mixture by CF4/O2 and O2/Ar Mixing Ratios. Plasma Chem. Plasma Process. 2017, 37, 1445–1462. [Google Scholar] [CrossRef]
  10. Hou, X.; Qiu, Y.; Yuan, E.; Zhang, X.; Liu, G. SO42−/TiO2 promotion on HZSM-5 for catalytic cracking of paraffin. Appl. Catal. A Gen. 2017, 537, 12–23. [Google Scholar] [CrossRef]
  11. Yang, Z.; Cao, J.P.; Retn, X.Y.; Zhao, X.Y.; Liu, S.N.; Guo, Z.X.; Shen, W.Z.; Bai, J.; Wei, X.Y. Preparation of hierarchical HZSM-5 based sulfated zirconium solid acid catalyst for catalytic upgrading of pyrolysis vapors from lignite pyrolysis. Fuel 2019, 237, 1079–1085. [Google Scholar] [CrossRef]
  12. de Rivas, B.; Sampedro, C.; Ramos-Fernandez, E.V.; Lopez-Fonseca, R.; Gascon, J.; Makkee, M.; Gutiérrez-Ortiz, J.I. Influence of the synthesis route on the catalytic oxidation of 1,2-dichloroethane over CeO2/H-ZSM5 catalysts. Appl. Catal. A Gen. 2013, 456, 96–104. [Google Scholar] [CrossRef]
  13. Joshi, Y.V.; Thomson, K.T. The roles of gallium hydride and Brønsted acidity in light alkane dehydrogenation mechanisms using Ga-exchanged HZSM-5 catalysts: A DFT pathway analysis. Catal. Today 2005, 105, 106–121. [Google Scholar] [CrossRef]
  14. Zhan, W.; Guo, Y.; Gong, X.; Guo, Y.; Wang, Y. Current status and perspectives of rare earth catalytic materials and catalysis. Chin. J. Catal. 2014, 35, 1238–1250. [Google Scholar] [CrossRef]
  15. Dai, Q.; Wang, W.; Wang, X.; Lu, W. Sandwich-structured CeO2@ZSM-5 hybrid composites for catalytic oxidation of 1,2-dichloroethane: An integrated solution to coking and chlorine poisoning deactivation. Appl. Catal. B Environ. 2017, 203, 31–42. [Google Scholar] [CrossRef]
  16. Chen, X.; Yu, E.; Cai, S.; Jia, H.; Chen, J.; Liang, P. In situ pyrolysis of Ce-MOF to prepare CeO2 catalyst with obviously improved catalytic performance for toluene combustion. Chem. Eng. J. 2018, 344, 469–479. [Google Scholar] [CrossRef]
  17. Jia, W.; Wu, Q.; Lang, X.; Hu, C.; Zhao, G.; Li, J.; Zhu, Z. Influence of Lewis Acidity on Catalytic Activity of the Porous Alumina for Dehydrofluorination of 1,1,1,2-Tetrafluoroethane to Trifluoroethylene. Catal. Lett. 2015, 145, 654–661. [Google Scholar] [CrossRef]
  18. Mekhemer, G.A.H.; Khalaf, H.A.; Mansour, S.A.A.; Nohman, A.K.H. Sulfated Alumina Catalysts: Consequences of Sulfate Content and Source. Mon. Für Chem./Chem. Mon. 2005, 136, 2007–2016. [Google Scholar] [CrossRef]
  19. Song, J.Y.; Chung, S.H.; Kim, M.S.; Seo, M.G.; Lee, Y.H.; Lee, K.Y.; Kim, J.S. The catalytic decomposition of CF4 over Ce/Al2O3 modified by a cerium sulfate precursor. J. Mol. Catal. A Chem. 2013, 370, 50–55. [Google Scholar] [CrossRef]
  20. Xu, X.; Jeon, J.Y.; Choi, M.H.; Kim, H.Y.; Choi, W.C.; Park, Y.K. A Strategy to Protect Al2O3-based PFC Decomposition Catalyst from Deactivation. Chem. Lett. 2005, 34, 364–365. [Google Scholar] [CrossRef]
  21. El-Bahy, Z.; Ohnishi, R.; Ichikawa, M. Hydrolysis of CF4 over alumina-based binary metal oxide catalysts. Appl. Catal. B Environ. 2003, 40, 81–91. [Google Scholar] [CrossRef]
  22. Takita, Y.; Morita, C.; Ninomiya, M.; Wakamatsu, H.; Nishiguchi, H.; Ishihara, T. Catalytic Decomposition of CF4 over AlPO4-Based Catalysts. Chem. Lett. 1999, 28, 417–418. [Google Scholar] [CrossRef]
  23. Dwivedi, U.; Naik, S.N.; Pant, K.K. High quality liquid fuel production from waste plastics via two-step cracking route in a bottom-up approach using bi-functional Fe/HZSM-5 catalyst. Waste Manag. 2021, 132, 151–161. [Google Scholar] [CrossRef] [PubMed]
  24. Liu, Y.; Ma, C.; Zhang, Q.; Pan, P.; Gu, L.; Xu, D.; Bao, J.; Dai, Z. 2D Electron Gas and Oxygen Vacancy Induced High Oxygen Evolution Performances for Advanced Co3O4/CeO2 Nanohybrids. Adv. Mater. 2019, 31, 1900062. [Google Scholar] [CrossRef] [PubMed]
  25. Takita, Y.; Ninomiya, M.; Miyake, H.; Wakamatsu, H.; Yoshinaga, Y.; Ishihara, T. Catalytic decomposition of perfluorocarbons Part II. Decomposition of CF4 over AlPO4-rare earth phosphate catalysts. Phys. Chem. Chem. Phys. 1999, 1, 4501–4504. [Google Scholar] [CrossRef]
  26. Panda, A.K.; Mishra, B.G.; Mishra, D.K.; Singh, R.K. Effect of sulphuric acid treatment on the physico-chemical characteristics of kaolin clay. Colloids Surf. A Physicochem. Eng. Asp. 2010, 363, 98–104. [Google Scholar] [CrossRef]
  27. Stanciulescu, M.; Bulsink, P.; Caravaggio, G.; Nossova, L.; Burich, R. NH3-TPD-MS study of Ce effect on the surface of Mn- or Fe-exchanged zeolites for selective catalytic reduction of NOx by ammonia. Appl. Surf. Sci. 2014, 300, 201–207. [Google Scholar] [CrossRef]
  28. Benaliouche, F.; Boucheffa, Y.; Ayrault, P.; Mignard, S.; Magnoux, P. NH3-TPD and FTIR spectroscopy of pyridine adsorption studies for characterization of Ag- and Cu-exchanged X zeolites. Microporous Mesoporous Mater. 2008, 111, 80–88. [Google Scholar] [CrossRef]
  29. Luo, J.; Kamasamudram, K.; Currier, N.; Yezerets, A. NH3-TPD methodology for quantifying hydrothermal aging of Cu/SSZ-13 SCR catalysts. Chem. Eng. Sci. 2018, 190, 60–67. [Google Scholar] [CrossRef]
  30. Xu, X.; Jeon, J.Y.; Choi, M.H.; Kim, H.Y.; Choi, W.C.; Park, Y.K. The modification and stability of γ-Al2O3 based catalysts for hydrolytic decomposition of CF4. J. Mol. Catal. A Chem. 2007, 266, 131–138. [Google Scholar] [CrossRef]
  31. Damyanova, S.; Centeno, M.; Petrov, L.; Grange, P. Fourier transform infrared spectroscopic study of surface acidity by pyridine adsorption on Mo/ZrO2–SiO2(Al2O3) catalysts. Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 2001, 57, 2495–2501. [Google Scholar] [CrossRef]
  32. Takita, Y.; Anabe, T.; Ito, M.; Ogura, M.; Muraya, T.; Yasuda, S.; Nishiguchi, H.; Ishihara, T. Decomposition of CH2FCF3 (134a) over Metal Phosphate Catalysts. Ind. Eng. Chem. Res. 2002, 41, 2585–2590. [Google Scholar] [CrossRef]
  33. Swamidoss, C.M.A.; Sheraz, M.; Anus, A.; Jeong, S.; Park, Y.-K.; Kim, Y.-M.; Kim, S. Effect of Mg/Al2O3 and Calcination Temperature on the Catalytic Decomposition of HFC-134a. Catalysts 2019, 9, 270. [Google Scholar] [CrossRef] [Green Version]
  34. Takita, Y.; Moriyama, J.-I.; Nishiguchi, H.; Ishihara, T.; Hayano, F.; Nakajo, T. Decomposition of CCl2F2 over metal sulfate catalysts. Catal. Today 2004, 88, 103–109. [Google Scholar] [CrossRef]
  35. Wang, T.; Liu, H.; Zhang, X.; Liu, J.; Zhang, Y.; Guo, Y.; Sun, B. Catalytic conversion of NO assisted by plasma over Mn-Ce/ZSM5-multi-walled carbon nanotubes composites: Investigation of acidity, activity and stability of catalyst in the synergic system. Appl. Surf. Sci. 2018, 457, 187–199. [Google Scholar] [CrossRef]
  36. Zhao, H.; Zhao, H.; Han, W.; Dong, F.; Tang, Z. Enhanced catalytic performance of Nb doping Ce supported on ordered mesoporous TiO2-SiO2 catalysts for catalytic elimination of 1,2-dichlorobenzene. Mol. Catal. 2019, 479, 110638. [Google Scholar] [CrossRef]
  37. Liu, B.; Li, C.; Zhang, G.; Yao, X.; Chuang, S.S.C.; Li, Z. Oxygen Vacancy Promoting Dimethyl Carbonate Synthesis from CO2 and Methanol over Zr-Doped CeO2 Nanorods. ACS Catal. 2018, 8, 10446–10456. [Google Scholar] [CrossRef]
  38. Zong, L.; Zhang, G.; Zhao, H.; Zhang, J.; Tang, Z. One pot synthesized CeO2-WO3-TiO2 catalysts with enriched TiO2 (001) facets for selective catalytic reduction of NO with NH3 by evaporation-induced self-assembly method. Chem. Eng. J. 2018, 354, 295–303. [Google Scholar] [CrossRef]
  39. Han, W.; Zhao, H.; Dong, F.; Tang, Z. Morphology-controlled synthesis of 3D, mesoporous, rosette-like CeCoOx catalysts by pyrolysis of Ce[Co(CN)6] and application for the catalytic combustion of toluene. Nanoscale 2018, 10, 21307–21319. [Google Scholar] [CrossRef]
Polymers 14 02717 g001 550
Figure 1. SEM of (A) HZSM-5, (B) Ce/HZSM-5, (C,D) S/Ce/HZSM-5, and SEM-EDS mapping for S/Ce/HZSM-5 (E–I).
Figure 1. SEM of (A) HZSM-5, (B) Ce/HZSM-5, (C,D) S/Ce/HZSM-5, and SEM-EDS mapping for S/Ce/HZSM-5 (E–I).
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Figure 2. X-ray diffraction (XRD) patterns of the catalysts, (1) HZSM-5, (2) Ce/HZSM-5, and (3) S/Ce/HZSM-5.
Figure 2. X-ray diffraction (XRD) patterns of the catalysts, (1) HZSM-5, (2) Ce/HZSM-5, and (3) S/Ce/HZSM-5.
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Figure 3. NH3-TPD profiles of catalysts.
Figure 3. NH3-TPD profiles of catalysts.
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Figure 4. FT-IR spectra of pyridine adsorption on catalysts.
Figure 4. FT-IR spectra of pyridine adsorption on catalysts.
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Figure 5. CF4 conversion reaction over catalysts at different temperatures.
Figure 5. CF4 conversion reaction over catalysts at different temperatures.
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Figure 6. CF4 conversion over catalysts with time on stream.
Figure 6. CF4 conversion over catalysts with time on stream.
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Figure 7. Correlation between CF4 conversion and ratio of (strong + moderate)/weak and Lewis/Brønsted.
Figure 7. Correlation between CF4 conversion and ratio of (strong + moderate)/weak and Lewis/Brønsted.
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Polymers 14 02717 g008 550
Figure 8. X-ray photo electron spectroscopy (XPS) spectra of catalyst, (A): S 2p for catalyst, (B): O 1s for catalysts, and (C): Ce 3d for catalysts. (1) HZSM-5, (2) Ce/HZSM-5, and (3) S/Ce/HZSM-5.
Figure 8. X-ray photo electron spectroscopy (XPS) spectra of catalyst, (A): S 2p for catalyst, (B): O 1s for catalysts, and (C): Ce 3d for catalysts. (1) HZSM-5, (2) Ce/HZSM-5, and (3) S/Ce/HZSM-5.
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Table
Table 1. Specific surface area, pore diameter for the catalysts.
Table 1. Specific surface area, pore diameter for the catalysts.
CatalystsBET Surface Area (m2 g−1)Pore Diameter (nm)
HZSM-52482.38
Ce/HZSM-51482.28
S/Ce/HZSM-52782.63
Table
Table 2. NH3-TPD acidic sites results for the catalyst.
Table 2. NH3-TPD acidic sites results for the catalyst.
CatalystsAmount of Acid Site (µmol g−1)
WeakModerateStrongTotal(Strong + Moderate)/Weak
HZSM-566326709300.40
Ce/HZSM-529054408341.88
S/Ce/HZSM-5273855127424027.80
Table
Table 3. FT-IR spectra of pyridine adsorption results for the catalyst.
Table 3. FT-IR spectra of pyridine adsorption results for the catalyst.
CatalystsAmount of Acid Site (µmol g−1)
L-Acid SiteB-Acid SiteLewis/Brønsted (L/B)
HZSM-5120.57233.910.52
Ce/HZSM-5138.2683.611.65
S/Ce/HZSM-5156.8469.972.24
Table
Table 4. Surface atomic distribution of element O and Ce.
Table 4. Surface atomic distribution of element O and Ce.
CatalystsDistribution (%)
OlatOsurOadsCe3+/Ce
HZSM-500100/
Ce/HZSM-510.522.067.525.9
S/Ce/HZSM-5010.189.931.0
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Zheng, X.; Chen, S.; Liu, W.; Xiang, K.; Liu, H. The Design of Sulfated Ce/HZSM-5 for Catalytic Decomposition of CF4. Polymers 2022, 14, 2717. https://doi.org/10.3390/polym14132717

AMA Style

Zheng X, Chen S, Liu W, Xiang K, Liu H. The Design of Sulfated Ce/HZSM-5 for Catalytic Decomposition of CF4. Polymers. 2022; 14(13):2717. https://doi.org/10.3390/polym14132717

Chicago/Turabian Style

Zheng, Xie, Shijie Chen, Wanning Liu, Kaisong Xiang, and Hui Liu. 2022. "The Design of Sulfated Ce/HZSM-5 for Catalytic Decomposition of CF4" Polymers 14, no. 13: 2717. https://doi.org/10.3390/polym14132717

APA Style

Zheng, X., Chen, S., Liu, W., Xiang, K., & Liu, H. (2022). The Design of Sulfated Ce/HZSM-5 for Catalytic Decomposition of CF4. Polymers, 14(13), 2717. https://doi.org/10.3390/polym14132717

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